B1772

SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: B1772: Seat Position Sensor Circuit Malfunction
B1772 - Seat Position Sensor Circuit Malfunction

DESCRIPTION

The seat position sensor circuit consists of the occupant classification ECU and the seat position airbag sensor (passenger side).

The seat position airbag sensor sends the seat position signal to the occupant classification ECU to control the dual stage deployment of the front passenger airbag.

DTC B1772 is recorded when a malfunction is detected in the seat position sensor circuit.





HINT
When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU, and perform troubleshooting for those DTCs first.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
* If troubleshooting (wire harness inspection) is difficult to perform, remove the passenger seat installation bolts to access the underside of the seat cushion.
* In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may damage the seat or deform the seat rails. Hold the seat only as necessary.

PROCEDURE

1. CHECK CONNECTORS

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal.

(c) Check that the connectors are properly connected to the occupant classification ECU and the seat position airbag sensor (passenger side).

OK:

The connectors are properly connected.

HINT
If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

(d) Disconnect the connectors from the occupant classification ECU and the seat position airbag sensor (passenger side).

(e) Check that the terminals of the connectors are not damaged.

OK:

The terminals are not deformed or damaged.

NG -- REPLACE FRONT SEAT WIRE RH
OK -- Continue to next step.

2. CHECK FRONT SEAT WIRE RH (SHORT TO B+)

(a) Connect the cable to the negative (-) battery terminal.





(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





NG -- REPLACE FRONT SEAT WIRE RH
OK -- Continue to next step.

3. CHECK FRONT SEAT WIRE RH (OPEN)

(a) Turn the ignition switch off.





(b) Disconnect the cable from the negative (-) battery terminal.

(c) Using SST, connect terminals 2 (SP) and 1 (GSP) of connector C.

NOTICE:
Do not forcibly insert SST into the terminals of the connector.

SST : 09843-18040

(d) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPLACE FRONT SEAT WIRE RH
OK -- Continue to next step.

4. CHECK FRONT SEAT WIRE RH (SHORT TO GROUND)

(a) Disconnect SST from connector C.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPLACE FRONT SEAT WIRE RH
OK -- Continue to next step.

5. CHECK FRONT SEAT WIRE RH (SHORT)

(a) Measure the resistance according to the value(s) in the table below.





Standard Resistance:





NG -- REPLACE FRONT SEAT WIRE RH
OK -- Continue to next step.

6. CHECK FOR DTC

(a) Connect the connectors to the occupant classification ECU and the seat position airbag sensor (passenger side).

(b) Connect the cable to the negative (-) battery terminal.

(c) Turn the ignition switch to ON.

(d) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(e) Clear the DTCs stored in the center airbag sensor assembly Reading and Clearing Diagnostic Trouble Codes.

(f) Turn the ignition switch off.

(g) Turn the ignition switch to ON.

(h) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

OK:

DTC B1772 is not output.

HINT
DTCs other than B1772 may be output at this time, but they are not related to this check.

NG -- INSPECT SEAT POSITION AIRBAG SENSOR (PASSENGER SIDE)

OK -- USE SIMULATION METHOD TO CHECK Diagnosis System

7. INSPECT SEAT POSITION AIRBAG SENSOR (PASSENGER SIDE)

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal.

(c) Replace the seat position airbag sensor with a known good part (passenger side) Removal.

HINT
* Perform an inspection using known good parts from another vehicle if possible.
* The seat position airbag sensor is installed on the driver side.

(d) Connect the cable to the negative (-) battery terminal.

(e) Turn the ignition switch to ON.

(f) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(g) Clear the DTCs stored in the center airbag sensor assembly Reading and Clearing Diagnostic Trouble Codes.

(h) Turn the ignition switch off.

(i) Turn the ignition switch to ON.

(j) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

OK:

DTC B1772 is not output.

HINT
DTCs other than B1772 may be output at this time, but they are not related to this check.

NG -- REPLACE FRONT SEAT CUSHION ASSEMBLY

OK -- END

8. REPLACE FRONT SEAT CUSHION ASSEMBLY

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal.

(c) Replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor) Removal.

(d) Connect the cable to the negative (-) battery terminal.

(e) Turn the ignition switch to ON.

(f) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(g) Clear the DTCs stored in the center airbag sensor assembly Reading and Clearing Diagnostic Trouble Codes.

(h) Turn the ignition switch off.

(i) Turn the ignition switch to ON.

(j) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

OK:

DTC is not output.

NEXT -- Continue to next step.

9. PERFORM ZERO POINT CALIBRATION

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Using the Techstream, perform zero point calibration Programming and Relearning.

(d) Turn the ignition switch off.

(e) Turn the ignition switch to ON.

(f) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

HINT
If the DTCs are not cleared at this time, past DTCs will remain.

NEXT -- Continue to next step.

10. PERFORM SENSITIVITY CHECK

(a) Perform the sensitivity check Programming and Relearning.

NEXT -- END